Bacterial Skin Infections Flashcards
etiology of impetigo
s aureus or s pyogenes
- dirty fingernails
- other children
- day care centers
- crowded housing areas
skin findings in non-bullous impetigo
- sites: face or extremities after trauma
- papules -> vesicles -> pustules -> rupture -> honey colored crusted papules on erythematous base
skin findings in bullous impetigo
- flaccid bullae
- ruptured bullae leave circinate, weepy or crusted lesions
- sites: face, extremities, perineum
management of impetigo
- proper hand washing
- clean lesion with soap and water
- fomite control
- topical or oral antibiotic: mupirocin 2% ointment, fusidic acid
- widespread and deeper lesions: systemic antibiotics + topical therapy (dicloxacillin or cephalexin, erythromycin, coamoxiclav)
drugs for mrsa
doxycycline, clindamycin, cotrimoxazole
prevention of impetigo if recurrent
- nasal decolonization with mupirocin ointment daily for 5-10 days
- body decolonization with chlorhexidine for 5-14 days
- bleach bath 2x weekly for 3 mos
etiology of ecthyma
staphylococcus and/or streptococcus
skin findings in ecthyma
- ulcerative pyoderma that extends deep into dermis
- punched out ulcers with thick grayish yellow crust, erythematous elevated borders
- superficial saucer shaped ulcer with raw base and elevated edges
- heal with scarring
- site: lower extremities
predisposing factors to ecthyma
poor hygiene, malnutrition, trauma, diabetes
treatment for ecthyma
- clean with soap
- topical or oral antibiotics (mupirocin ointment, oral dicloxacillin, 1st gen cephalosporin)
an acute, round, tender, circumscribed perifollicular abscess that ends in central suppuration
furuncle in furunculosis
what are carbuncles
- extremely painful lesion at the nape, back, or thighs
- deeper inflammatory lesion when furuncles coalesce
skin findings in carbuncles
- red and indurated, multiple pustules, drains externally around multiple hair follicles
- yellow gray irregular crater at center
- heals with scarring
etiology of furunculosis and carbunculosis
s aureus
course of carbuncles and furuncles
- central necrosis -> rupture -> purulent discharge + necrotic debris
- sites: nape, axilla, buttocks, thighs
treatment for furunculosis and carbunculosis
- early stage: warm compress + antibiotic
- fluctuant: incision and drainage
- handwashing, chlorhexidine wash, bleach bath
etiology of cellulitis
gabhs and s aureus
skin findings in cellulitis
- ill defined erythema and edema, warmth and pain of affected area
- bulla formation and superficial necrosis -> epidermal sloughing or erosions
- site: lower extremity, UNILATERAL
risk factors and labs for cellulitis
- rf: disrupted skin barrier (toe web infection), immunocompromised, age, obesity, renal or hepatic disease
- leukocytosis >/= 10,000, elevated esr, elevated crp
management of nonpurulent cellulitis
- first line: cephalexin, dicloxacillin, penicillin v
- second line: clindamycin, macrolides
management of purulent cellulitis
- incise and drain, culture
- mssa: cephalexin, dicloxacillin
- mrsa: clindamycin, tetracycline, tmp-smx
treatment duration of cellulitis
- uncomplicated: 5-10 d
- immunocompromised: 7-14 d
- reassess after 24-72 hr
- treat predisposing factors
indications for parenteral antibiotics in cellulitis
at least 2 or more:
- t >38C or <36 C
- pr >90 bpm
- rr >20/min
- wbc >12,000 or < 4,000
- failed outpatient treatment
etiology of erysipelas
gabhs/gc/gg
skin findings in erysipela
- sharply marginated, deep red, edematous plaques
- painful and warm
- site: superficial dermal lymphatic vessels of leg
- erythematous patch -> peripheral extension
clinical findings in erysipelas
- preceded by fever, chills, vomiting, joint pains
- leukocytosis >20,000
complications of erysipelas
septicemia, deep cellulitis, necrotizing fasciitis, abscess
ddx for erysipelas
contact dermatitis, lupus erythematosis
treatment for erysipelas
- uncomplicated: oral antibiotics (penicillin v, amoxicillin, clindamycin, macrolides)
- leg elevation, ice bags, cold compress
- treat predisposing factors
improvement in 24-48 hrs, 10 days for skin
etiology of green nail syndrome
p aeruginosa
- hands frequently submerged in water
nail findings in green nail syndrome
- onycholysis
- green discoloration of distal portion of nail
- paronychia
treatment for green nail syndrome
- 1% acetic acid soln
- neosporin
- keep hands dry, avoid trauma
how to get pseudomonas folliculitis
contaminated baths in the past 2 weeks
skin findings of p folliculitis
- sudden onset pruritic follicular, maculopapular, vesicular, pustular lesions
- 1-4 days after bath
- sites: sides of trunk, axillae, breasts, buttocks, proximal extremities
management of p folliculitis
- self-limiting within 7-14 days
- fever and constitutional symptoms: 3rd gen cephalosporin or fluoroquinolone (ciprofloxacin or ofloxacin)
etiology of pyogenic paronychia
s aureus
skin findings in pyogenic paronychia
- painful, tender, red swelling of skin surrounding fingernail
- can progress to abscess
- primary disposing factor: separation of cuticle from nail plate
management of pyogenic paronychia
- keep nails dry, gloves
- incision and drainage
- suppurative = oral antibiotic: penicillin or cephalosporin
